SOFIA, Feb 7 (Reuters) - NATO member Bulgaria approved a decision on Wednesday to extend the mission of its troops in Iraq by a year, the government said. Bulgaria will send 155 soldiers to Iraq to replace 120 troops and 35 support personnel who are there now, the cabinet said in a statement. They will go in March, when the mission was originally to end. The new contingent will guard an Iranian refugee camp in Ashraf, 70 km (40 miles) north of Baghdad until March, 2008. The decision must still be approved by parliament.