Police commanders from British cities hit by rioting during the past 11 days will meet here with government officials Wednesday to assess efforts to control the disturbances and discuss the government's offer of military-style riot control equipment.

A number of senior police officers also went today to British-ruled Northern Ireland to confer with officers of the Royal Ulster Constabulary, who use or have previously tried the plastic bullets, armored vehicles, tear gas and water cannon being made available by the government to chief constables in England who want it. Groups of chief constables watched tests of water cannon and armored vehicles at Army depots in England.

But many chief constables have told the government, according to officials, that they do not want to use any of this equipment unless the disorders, which now appear to be subsiding, become much worse. Chief Constable Kenneth Oxford of Liverpool said tonight he wanted armored vehicles and better protective gear for his officers if there were more trouble, although he said he was reluctant to use water cannon.

Oxford ordered the use of tear gas for the first time in mainland Britain last week in Liverpool to help quell the worst of the rioting that spread at one point to more than 30 cities and towns. Nearly 1,000 police, more than half them in Liverpool, have been injured and more than 2,000 rioters arrested across the country since July 3.

The water cannon being offered police by the government is now used in several European countries to disperse rioters. The armored personnel carriers would be Army castoffs, like those used by the Army in Northern Ireland, but painted police blue. Plastic bullets fired by special riot guns are frequently used by British soldiers in Northern Ireland against firebomb-throwing attackers. They have caused serious injuries and some deaths when the bullets have struck victims directly, usually in the head, instead of the impact being blunted by being fired into the ground first. No one has yet died in the urban rioting here.

Police in Liverpool used gas last week for the first time in mainland Britain to quell the worst of the rioting that spread at one point to more than 30 cities and towns. Nearly 1,000 police officers have been injured and more than 2,000 rioters have been arrested.

But on recent nights, the number and intensity of disturbances, now largely confined to a half dozen industrial cities in northern England, have significantly declined. Police blame most of the remaining trouble on relatively small gangs of; youths, both black and white, smashing store windows and battling police after the pubs close.

The most serious trouble overnight, which included molotov cocktail attacks on police in Leicester and Derby, was contained by reinforced numbers of police still on emergency duty.

Noting that the violence has been decreasing "both quantitatively and qualitatively" as police better control it, Prime Minister Margaret Thatcher is moving cautiously in response to the most important, difficult challenge she has faced as prime minister, according to government sources.

She has primarily provided the police strong public backing and approved steps giving them more resources to cope with further outbreaks of violence. But she has not yet approved potentially controversial riot control legislation sought by the vocal right wing of her own Conservative Party or expensive measures to ease unemployment and aid inner cities championed by left-wing Conservatives and the opposition labor Party.

"She is trying to walk on tightrope on this," said one Thatcher aide.

"This is no time for detailed analysis," Thatcher said in Parliament today in response to questions about possible underlying causes of the urban violence. "We are not going to be able to deal in practice with the economic and social aspects of it until law is restored and seen to be restored. The two things go hand in hand."

Thatcher's stance came under political attack tonight from leaders of the centrist Social Democratic and Liberal parties. They are hoping to embarrass Thatcher by wining a large share of the Conservative vote for their candidate, Social Democrat Roy Jenkins, in a closely watched parliamentary by-election on Thursday in Warrington, a northern industrial city and Labor Party stronghold located between Liverpool and Manchester, where much of the worst rioting occurred last week.

Social Democratic leader Shirley Williams, a former Labor Party Cabinet minister, accused Thatcher of ignoring the causes of the "summer fever" of rioting while only treating its symptoms with riot control equipment for the police. Williams said, "Supporting the police is not enough. There has to be a response dealing with the genuine and bitter grievances of young people."

The "unemployment medicine" of Thatcher's monetarist economic policies was singled out by Liberal Party Leader David Steel. "I do not say that unemployment is the sole cause of the riots," he said. "But as Mrs. Thatcher's nanny could have told her, idle hands find mischief."

Currency traders, analyzing a sharp drop in the value of the pound in recent days to $1.86, have said there appears to be international money market concern about the disorders and the effect they may have on the British economy and Thatcher's policies.

Financial realities leave Thatcher little room to maneuver, however, according to her aides. Her Treasury ministers already are fighting a growing budget deficit because cuts in some government spending are being more than offset by increases in unemployment compensation and aid to government-owned industries during the severe recession. Now the government must pay compensation to businesses that suffered still uncounted millions in riot damage.

Officials hinted that a new minister of inner cities, who would be asked to better coordinate government aid to British cities, might be announced during an all-day parliamentary debate Thursday on the riots.