The South Pars gas complex in the Persian Gulf forms one of the largest offshore natural gas fields. By Iran's estimate, its portion of the field, which it shares with Qatar, holds about 8 percent of the world's natural gas reserves.
Iranian Oil Minister Rostam Qasemi said the government was frustrated with delays by CNPC for work in its section of the offshore field.
Mousa Souri, managing director of Pars Oil and Gas Co., said CNPC must start work on the project by the end of the Iranian year in March.
"Iran is dissatisfied with CNPC's frequent delaying of Phase 11 of South Pars development," he was quoted by the Tehran Times as saying.
CNPC replaced French energy company Total at the project in 2009. Political and economic pressure on Iran has made some energy companies reluctant to move forward with major energy projects in the country.