Poland's powerful new independent unions threatened today to stage another strike against the government as a asign of displeasure at the slow pace of official recognition of their new movement.

The union threat, coupled with a Sunday meeting of foreign ministers of the Warsaw Pact in the Polish capital, reflects the internal and external pressures of the Polish leadership to avoid new upheavals in its six-week-old labor confrontation.

The Soviet Bloc ministers usually meet twice a year, each time at a different capital, and officials here say it was coincidential that it is Warsaw's turn to play host. The meeting, nevertheless, is likely all the same to push to the center of attention the continued political and economic flux in Poland -- a situation that has drawn expressions of concern from Warsaw's allies.

Both East German and Czechslovak leaders have explicitly warned within the past week that they would not tolerate basic changes in the politicial order in Poland.

The Warsaw Pact foreign ministers' meeting was preceded by a meeting of top-level military officials that ended today in Prague.

The independent unions staged a dramatic one-hour strike across Poland two weeks ago to express their displeasure at what they see as government foot-dragging. Today the union federation issued a new strike threat, saying, "If the authorities do not register Solidarity in the near future, it will mean they want to force us into a new strike. The nonregisteration of Solidarity will be tantamount to breaking the Gdansk agreement."

Lech Walesa, leader of the Solidarity free trade union federation, came from Gdansk to Warsaw today to meet with other members of the parlimentary legal commission that is working on a new labor law and revisions of the Polish labor code. It was the first stop for Walesa in what is a planned five-day tour that will take the labor leader to Krakow in the south and the mining region of Silesia in a personal bid to strengthen the young labor organization.

Government officials indicated privately today that there may be a compromise on the registration issue and that the Warsaw court may give its approval early Saturday or "within one dozen days," as one well-informed source put it.

The action has been held up by a government objection to the absence of an explicit pledge of allegiance to the Polish Communist Party in the national labor organization's charter. Such a pledge was included in the final agreement signed by strikers and government officials in Gdansk Aug. 31.

In addition, the government differs with union organizers over what the legal status of the federation's 49 regional branches should be if the national union registers as a whole.

The charters of 12 smaller independent unions have already been approved by the Warsaw court responsible for registering the new groups, but the national federation Solidarity is by far the largest, now claiming a membership of 8 million workers.

As a future sign of the new movement's stunning strength, the old official trade union council bowed to the inevitable this week by indicating that it would dissolve next month and set up a liquidation commission to dispose of its funds and property. Once the powerful representative of Polish workers, the council has virtually lost all its members either to the new free unions or to old branch unions which have chosen to withdraw from the council and set themselves up at "independent."

While registration is keenly desired by the new groups, union leaders have been able to act with unquestioned authority, obtaining office space and bank accounts and gradually overcoming pockets of resistance in sections of Poland. a

With formal recognition begins the key period of testing the stability of the new balance of political forces that has emerged within the country. From the organizing stage the new unions must ove on to more active participation in the management of the Polish economy and the restoration of peace.

Government officials say that the economy has been severely disrupted as a result of production losses during the strike. Moreover, there has been a sharp fall in productivity since in many factories, since much time is devoted to political discussions rather than work.

The supply of coal, Poland's chief export, is well below demand and foreign ships waiting to load in the northern Baltic ports are facing lengthy delays. The drop in production has been attributed to the abandoning of an unpopular shift system in Silesian mines designed to ensure continuous work in the shafts.

Figures released by the government this week show the Polish economy rebounded slightly in September over its disasterous performance during the strikebound month of August, but production remains below last year's level.

Industrial production was reported up 9.8 percent in September over the month before, but still 7 percent below the same month last year.

Coal production during the first nine months of this year is said to be running 4.5 million tons short of the projected level, and only 41 percent of planning housing construction was completed.