Priyanka Gandhi Vadra is an "invaluable asset" to Congress president Rahul Gandhi and will help galvanise support for the party in the Lok Sabha election as she is charismatic and has a very effective way of communicating, senior party leader Kapil Sibal has said.

He also said it would not be right to compare the stitching of alliances by the BJP and the Congress as the ruling party had a majority, while the opposition party was down to 44 in the last polls and has to re-establish itself as the only alternative to the BJP.

In an interview to PTI, Sibal said Rahul Gandhi has established himself as the "prime challenger" to Prime Minister Narendra Modi.

"He is very forthright, very open, he is essentially democratic. I think he has taken the campaign into the battlefield," the former Union minister said.

Asked how he sees Priyanka Gandhi Vadra's entry into active politics and her campaigning for the party in the Lok Sabha polls, Sibal said, "She will galvanise a lot of votes, she will galvanise a lot of support for the Congress. She will also galvanise a lot of women voters, and the young."

"She is charismatic, she has a way of communicating which is very effective. She speaks from the heart. So, I think she is an invaluable asset to Rahul Gandhi," he said.

Priyanka and Jyotiraditya Scindia took charge as AICC general secretaries in charge of eastern Uttar Pradesh and western UP respectively last month.

On why the Congress was still in the process of stitching up alliances while the BJP seems battle ready with its tie-ups, the 70-year-old leader said there should be no comparison between the two parties when it comes to alliances.

"You must remember that in the last Lok Sabha elections, the BJP alone got a majority. So it is easier for them to stitch alliances...they can actually find it fairly easy to stitch alliances with some of their minority partners like JD(U), Shiv Sena, the Akalis who have been their traditional allies," he said.

However, the BJP has not had any new alliances, and have lost a lot of the alliance partners, he claimed.

"Congress is in a difficult position because we got only 44 seats, so we wish to re-establish the fact that we are the only alternative to the BJP and the regional parties are keen to extend their footprint beyond their region where they are a strong force," Sibal said.

This inherent tension does not exist between the BJP and its alliance partners, he said.

"Therefore, it takes time. But I feel that alliances will happen. They have happened in Tamil Nadu, they have happened in Maharashtra, they have happened in other states," he said, hoping that there would be post-poll alliances as well among the opposition parties.