LONDON (AP) _ The government put army ambulances on the streets of London Wednesday night after regular ambulance crews, embroiled in a pay dispute, said they would handle emergency calls only.

An eight-week work-to-rule dispute escalated Tuesday when 2,500 regular ambulance crewmen and women in charge of 455 ambulances at 71 ambulance depots were suspended without pay because of their refusal to handle all calls.

Calls for ambulances were rerouted to police and volunteer ambulance crews, with 51 army ambulances mobilized Wednesday night to assist.

The last time army ambulances were used was during the wave of public service pay strikes in the winter of 1978-79.

Health Secretary Kenneth Clarke said in an interview with British Broadcasting Corp. radio that he regretted calling on the army but that the unions ''are still insisting on 11.4 percent .. . and they are prepared to take industrial action in support of that.''

The government has offered a pay increase of 6.5 percent.

Ambulance staff now earn just over $16,900 a year after five years on the job. The crews have asked the government to agree to arbitration.

Chris Humphreys, senior London officer for National Union of Public Employees, pleaded with Clarke not to deploy army ambulances.

''I have confirmed that ambulance staff will respond and not place any restrictions on the use of the radio in respect of all 999 calls, all calls for urgent assistance and queries,'' Humphreys said. The 999 code is the telephone number for ambulance and other emergency services in Britain.

Clarke has said army ambulances will be withdrawn only when union leaders agreed to resumption of normal ambulance services.