Young architectural practice DSDHA is emerging as a significant player after it won an appointment to work alongside Foster and Partners in central London.

The firm has been commissioned by More London to design two pavilions worth £1m on the south bank of the Thames, close to City Hall, as part of a Foster masterplan.

The first pavilion, which has received planning permission, will be on the edge of a small park, designed by landscape architect Gros Max. The park is in front of the Riverside 3 building, which will be occupied by law firm Norton Rose next year. The 30 m long pavilion will house a cafe, retail unit and service facilities for the park.

Deborah Saunt, DSDHA partner, said her practice had been collaborating with Foster and Partners and consulting engineer Robert Preston & Partners on the project.

She said: "This is the second time we have worked with Foster and we are learning to understand each other well.

"This pavilion will be a cantilevered shelter that will be used by the public as place to meet. It is the last link in the More London masterplan."

The second pavilion, which is up for planning permission this month, will be next to Tower Bridge and will have a wild-grass green roof.

DSDHA's other commission with Foster and Partners was for a joint masterplan for Parliament Square. This is due to be published next month. The designs are now complete, but remain secret because of security concerns. Sources close to the project say plans include closing the Westminster Abbey side of the square to traffic.