Prime Minister Robert Hawke announced today an early general election on Dec. 1 that is expected to be the most emotional and acrimonious in recent Australian history.

Hawke, whose Labor Party swept to power last year, said he called the election after only 18 months in power -- and 18 months ahead of time -- to save money by synchronizing voting for the Senate and House of Representatives, which are being expanded in a legislative reorganization.

Behind the stated reason, however, is Hawke's current status as the most popular political leader in Australian history and the low popularity of his rivals, including former foreign minister Andrew Peacock, who recently accused Hawke in Parliament of being a "little crook," a "perverter of the law" and an associate of criminals.

Recent opinion polls have put Hawke's approval rating consistently in the upper 60s and as high as 75 percent. Peacock, who heads the Liberal Party -- the senior party in the opposition conservative coalition with the rural-based National Party -- has rarely scored above 40 percent, and polls taken last month had him at an all-time low of 25 percent.

Peacock's charges three weeks ago of criminal involvement by Hawke, made under parliamentary privilege, were widely regarded as largely an emotional outburst.

Hawke has flatly denied them, and in a press conference last month, he broke down and wept when he began talking about the hurt he said the charges did to his family.

Several days later, Hawke's wife, Hazel, went on television to say that her children wanted to tell Australians that the younger of her two daughters, Rosslyn, 25, and her husband, Matt Dillon, 29, were undergoing treatment for heroin addiction.

The recent discovery of their addiction and the knowledge that the daughter had been physically affected by it with wasted lower limbs and a shortened life expectancy, reportedly had led to Hawke's public outburst of emotion.

Peacock expressed sympathy with the family's sorrow, but he took the hard political line that he had not raised the subject of his opponent's family and was hammering the crime issue by accusing the Hawke government of being soft on organized crime.

Peacock has made two specific allegations against Hawke.

First, he has charged that the prime minister prematurely closed down a royal crime investigating commission as its chairman, Melbourne lawyer Frank Costigan, was requesting more time for investigating the alleged major figures financing and organizing drug-running in Australia.

Secondly, Peacock alleged that the Hawke government had not given sufficient powers to the new national crime authority set up but not fully in operation yet to take over crime investigation from the Costigan commission.

A potentially explosive factor in the election campaign is that Costigan is scheduled to give the government his final report on four years of crime investigation by Oct. 31.

Peacock had demanded public disclosure of the report and Hawke has promised to do so, subject to any need to keep parts of it secret to assist investigations.

Already one famous figure with Labor Party connections, news media magnate Kerry Packer, has flatly denied any involvement in drugs or other crimes.

Packer, owner of a string of television and radio stations, magazines, ski resorts, and a coal mine among other interests is believed to be the second richest Australian after Rupert Murdoch.

Announcing the election date, Hawke repeated what he has said several times: that he will pursue organized criminals and put them behind bars, whoever they are.

Both he and Peacock said they believed the subject of organized crime would be an issue in the election, but only a secondary issue. They said they expected that the main issues would be economic, with Hawke standing on his government's record of bringing inflation down, expanding the economy and minimizing industrial disputes.

Peacock contends that the Australian economy is likely to deteriorate next year and that the Hawke government, if reelected, would have to take harsh measures, including new taxes on capital and wealth, to pay for the large deficit and income tax cuts in its budget.

Australians will be voting for the first time for a House of Representatives enlarged to 148 seats. In 1983, in the last election for a 125-seat House, Hawke's Labor Party won 75 seats, overthrowing the conservative government of Malcolm Fraser.

Fraser, a millionaire cattle and sheep rancher, left politics after that election and was replaced as leader of the Liberal Party by Peacock.

Hawke did not have to hold an election for the House of Representatives, where Australian governments are formed, until March l986.

But under the constitution, half the Australian Senate had to face the voters before next June. Such a Senate election was considered unlikely to have any effect on Hawke's ability to finish his full three-year term.