The deployment on the streets of Honiara comes after scores of homes and businesses, many run by local Chinese, were set ablaze during rioting sparked by the election of a new prime minister.
Police commissioner Shane Castles said on Thursday the situation in the city was calmer but remained tense.
"The security situation has been stabilised. However, whether the curfew continues (after Friday morning) will depend on what happens in the next 24 hours," said Castle.
The curfew from 6pm to 6am each day and within the city, includes the burned-out Chinatown area, the national parliament building, the city's wharves and central business district.
The rioting followed the election on Tuesday of Snyder Rini as prime minister, a step which angered the supporters of rival Job Dudley Tausinga.
Chinese businesses were a particular target because rioters believed they had backed Rini.
Rioters in Honiara set fire to
shops in the Chinatown district
Castle also said police were monitoring the port to ensure there was no influx of people from other provinces to aggravate the security situation.
He added that there was a disturbance at Auki, the capital of Malaita province, on Wednesday night and 14 people were arrested.
Rini, who is under protection in a secret location, has said he will not resign and has called for calm and talks to solve the Solomons political issues.
Most of the trouble had been confined to the capital on Guadalcanal island, which is next to Malaita, the most heavily populated province.
The violence in Honiara was the worst since the arrival in July 2003 of the Australian-led Regional Assistance Mission to Solomon Islands (RAMSI) to end years of civil strife.