You can serve them with a legal notice first and than file a writ petition in High Court against them for having a court order to allow you to participate in the tender process 

The Corrigendum has been released but if it was released prior to the date of expiry of submission of bids then you should have strong grounds to challenge the notification. A registered company can be justified depending upon the nature of work and many things.

This can be challenged in the high court.

You can file writ petition in HC against unjust tender conditions stipulated in corrigendum to tender 

No. It's not allowed bits unconstitutional and illegal. You can approach HC in writ for immediate direction to the appropriate authority If your complaint is not resolved

You say that you satisfy all the conditions and requirements as notified in tender notice. 

Whereas your company has not been registered under company's act, which is a lacuna on your side. 

The rules regarding invitation of tender will vary from one organization to another. 

You may first ascertain whether you have fulfilled all eligibility criteria,  confirm it as per rules and conditions prescribed for this tender and then plan to resort to legal action,  if it is really worth enough. 

Tender issuing authority has full right to decide eligibility. You have to incorporate company. Proprietorship not eligible.

1. Well the Organisation issuing Notice inviting Tender has the discretion to set the eligibility criteria. 

2. So even if you fulfill all conditions except one, it would be of no help and for not fulfilling one criterion is enough to disqualify. 

3. So looking for registered company alone is no discrimination against a proprietary concern. 

So challenging this condition would not be of much help. 

1. Tendering Agency have discretion to formulate their own individual terms & conditions and as yet there is no Govt. rules or regulations governing such agencies.

2. You can register your Prop. Firm under the Companies Act, as a "One Person Company (OPC)" and carry on your usual business without any exceptions. Registering process before ROC, would take about 10 odd days.

File a writ petition challenging the Corrigendum before the High court as same is discriminating and arbitrary .

1. This is not discrimination.

2. The condition of registration under Companies Act as an eligibility criteria is not per se unreasonable or arbitrary and certainly not illegal.

Dear Sir,

You are suggested to apply for the said tender and if rejected file the writ petition in High Court for such discrimination. Also, you may file an RTI to enquire as to why the discrimination and why only the company can apply for the tender. 

Hi 

Such discrimination of eligible bidders based on nature of bidding firm is prohibited in law. 

Government cannot discriminate between companies, partnership firms and proprietary firms and thereby limit the bidders to a government tender.

You should move the high court under Article 226 and obtain a stay in tendering process.

Hope this information is useful. 

You can file a writ Petitions under Article 226 of the Constitution of India in the High Court . 

It is not illegal, and that, it is also not discriminating.

However, if it is against principles of natural justice, you can file writ petition questioning the said corrigendum with respect to the tender issued by the Government.

You should file writ petition in High court against department under which the tender was published to remove this discrimination.