Turning down West Bengal Chief Minister Buddhadeb Bhattacharya's fresh offer of talks with the opposition on the Singur issue, Trinamool Congress chief Mamta Banerjee on Monday said the government must hold a referendum on the land acquisition issue.

"Government must go in for a referendum on land acquisition at Singur and Nandigram as also on the starvation deaths in closed tea gardens of North Bengal," she told reporters in Kolkata.

Asking the state government to return agricultural land to the farmers, the TC chief said, "Construction of the wall for the Tata Motors' small car project and talks cannot go side by side."

Alleging that the chief minister had thrown a challenge to the opposition parties at his Kisan rally on Sunday, Banerjee said, "We accept such a challenge."

She also alleged that the signing of the lease agreement between the state government and Tata Motors was shrouded in secrecy. "The chief minister is holding out threats to the opposition parties," she said.

"He (chief minister) must control his language like the kind he used at the Kisan rally yesterday," she said alleging, "he is flexing muscle power but we will not bow." The TC could not be stopped from agitating on the Singur and Nandigram issues. "You (Bhattacharya) can dictate to your party, but not us," she asserted.