"Despite the required assistance from the Centre, the Prem Kumar Dhumal-led BJP government has failed to carry out uniform development in Himachal," Singh said at a rally held here.
Putting an end to speculations on factionalism within the Congress in Himachal, senior party leaders, including Singh, Sharma, state party in-charge Virender Singh and state party chief Koul Singh Thakur, attended the rally.
Virbhadra Singh warned Chief Minister Dhumal against taking credit for projects "which were made possible by the UPA government".
The minister described the BJP government as the "most corrupt government the state has ever seen" and accused it of bestowing special benefits on Himachal Pradesh Cricket Association, which is led by Dhumal's son.
"Valuable land has been provided by the state government for HPCA's five-star hotel and stadium," he alleged.
Sharma, who holds the Commerce and Industry portfolio, targeted the BJP government, saying it levelled false charges against the Congress "with an intention to defame the party in the state".
He claimed that the state administrative machinery was in a "total mess" and the "Congress is united in its effort to oust BJP from power in Himachal."